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Toxoplasma gondii seropositivity and cognitive functions in school-aged children

Published online by Cambridge University Press:  20 May 2015

Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, USA
Department of Physical Therapy, Florida International University, Miami, Florida, USA
Department of Biostatistics, Florida International University, Miami, Florida, USA
Department of Occupational and Environmental Health, Florida International University, Miami, FL/South Florida Asthma Consortium, Ft. Lauderdale, Florida, USA
*Corresponding author. The University of Iowa, College of Public Health, S161 CPHB 105 River Street, Iowa City, Iowa 52242, USA. E-mail:


Toxoplasma gondii (T. gondii) infects one-third of the world population, but its association with cognitive functions in school-aged children is unclear. We examined the relationship between Toxoplasma seropositivity and neuropsychological tests scores (including math, reading, visuospatial reasoning and verbal memory) in 1755 school-aged children 12–16 years old who participated to the Third National Health and Nutrition Examination Survey, using multiple linear regressions adjusted for covariates. Toxoplasma seroprevalence was 7·7% and seropositivity to the parasite was associated with lower reading skills (regression coefficient [β] = −5·86, 95% confidence interval [CI]: −11·11, −0·61, P = 0·029) and memory capacities (β = −0·86, 95% CI: −1·58, −0·15, P = 0·017). The interaction between T. gondii seropositivity and vitamin E significantly correlated with memory scores. In subgroup analysis, Toxoplasma-associated memory impairment was worse in children with lower serum vitamin E concentrations (β = −1·61, 95% CI: −2·44, −0·77, P < 0·001) than in those with higher values (β = −0·12, 95% CI: −1·23, 0·99, P = 0·83). In conclusion, Toxoplasma seropositivity may be associated with reading and memory impairments in school-aged children. Serum vitamin E seems to modify the relationship between the parasitic infection and memory deficiency.

Research Article
Copyright © Cambridge University Press 2015 

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